First of all, thanks for your questions and hints.
The temperature is set to 25 C.
Can you please let me offer some further explanations,what do you mean by 'Turn off boundary diffusion too'? Thank you very much in advance.
Until now Species Model --> Options --> Full Multicomponent diffusion has been enabled, but right now I have disabled. After disabling the Full Multicomponent diffusion, the same concentration profile (with the same values) has been obtained for O2 as previously.
As a first approach I have thought to consider constant liquid-side mass transfer coefficient (calculated based on emprical rel.) and zero resistance for the gas-phase, and only after this to modify to be calculated considering a certain correlation.
Regarding to the Henry coefficient options, I have also performed the simulation considering the Van't Hoff correlation, but unfortunately the same result has been obtained as the first case presented (when Cinitial O2 bulk=4e-4 M, which is higher than the equilibrium concentration)
Can you pelase offer some further himts how can I solve this problem? Thank you very much in advance!